Commit 902d6d01 authored by Xiubo Li's avatar Xiubo Li Committed by Ilya Dryomov
Browse files

ceph: always queue a writeback when revoking the Fb caps 

In case there is 'Fw' dirty caps and 'CHECK_CAPS_FLUSH' is set we
will always ignore queue a writeback. Queue a writeback is very
important because it will block kclient flushing the snapcaps to
MDS and which will block MDS waiting for revoking the 'Fb' caps.

Link: https://tracker.ceph.com/issues/50223


Signed-off-by: default avatarXiubo Li <xiubli@redhat.com>
Reviewed-by: default avatarMilind Changire <mchangir@redhat.com>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent 841c3516

fs/ceph/caps.c

+24 −24
Original line number Diff line number Diff line
@@ -2156,6 +2156,30 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags) 
		      ceph_cap_string(cap->implemented),

		      ceph_cap_string(revoking));



		/* completed revocation? going down and there are no caps? */

		if (revoking) {

			if ((revoking & cap_used) == 0) {

				doutc(cl, "completed revocation of %s\n",

				      ceph_cap_string(cap->implemented & ~cap->issued));

				goto ack;

			}



			/*

			 * If the "i_wrbuffer_ref" was increased by mmap or generic

			 * cache write just before the ceph_check_caps() is called,

			 * the Fb capability revoking will fail this time. Then we

			 * must wait for the BDI's delayed work to flush the dirty

			 * pages and to release the "i_wrbuffer_ref", which will cost

			 * at most 5 seconds. That means the MDS needs to wait at

			 * most 5 seconds to finished the Fb capability's revocation.

			 *

			 * Let's queue a writeback for it.

			 */

			if (S_ISREG(inode->i_mode) && ci->i_wrbuffer_ref &&

			    (revoking & CEPH_CAP_FILE_BUFFER))

				queue_writeback = true;

		}



		if (cap == ci->i_auth_cap &&

		    (cap->issued & CEPH_CAP_FILE_WR)) {

			/* request larger max_size from MDS? */
@@ -2183,30 +2207,6 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags) 
			}

		}



		/* completed revocation? going down and there are no caps? */

		if (revoking) {

			if ((revoking & cap_used) == 0) {

				doutc(cl, "completed revocation of %s\n",

				      ceph_cap_string(cap->implemented & ~cap->issued));

				goto ack;

			}



			/*

			 * If the "i_wrbuffer_ref" was increased by mmap or generic

			 * cache write just before the ceph_check_caps() is called,

			 * the Fb capability revoking will fail this time. Then we

			 * must wait for the BDI's delayed work to flush the dirty

			 * pages and to release the "i_wrbuffer_ref", which will cost

			 * at most 5 seconds. That means the MDS needs to wait at

			 * most 5 seconds to finished the Fb capability's revocation.

			 *

			 * Let's queue a writeback for it.

			 */

			if (S_ISREG(inode->i_mode) && ci->i_wrbuffer_ref &&

			    (revoking & CEPH_CAP_FILE_BUFFER))

				queue_writeback = true;

		}



		/* want more caps from mds? */

		if (want & ~cap->mds_wanted) {

			if (want & ~(cap->mds_wanted | cap->issued))